A comparative study on room air conditioner performance of finned-tube evaporator and the micro-channel evaporator under optimal throttling condition.

Experimental investigations were conducted on refrigerant distributions in various throttling conditions in a 5-HP split room air conditioner (RAC) equipped with micro-channels. Experiment results show a tendency of abrupt decrease after a slight increase in both cooling capacity and EER when the width of expansion valve opening gradually increases. The best performance was obtained when the inlet pressure of the microchannel evaporator is 993.6kPa, which was confirmed in the analysis of refrigerant distribution mechanism revealed in the infrared thermographs. Comparisons are made between cooling capacity and EER of the RAC equipped with micro-channel evaporator working with the optimal throttling condition and those of a typical RAC equipped with a finned-tube evaporator with equal heat transfer area. The results reveal an average cooling capacity of the micro-channel evaporator RAC to be 4.8% higher than that of the finned-tube evaporator RAC and an average EER over 5% higher.